Question

Find the value of unknown resistance X in the following circuit, if no current flows through the section AD. Also calculate the current drawn by the circuit from the battery of emf 6 V and negligible internal resistance.

Answer 1

Since no current flows through AD. so the given circuit is a balanced Wheatstone bridge.

∴ The condition of balanced Wheatstone bridge is

\(\frac{P}{Q} = \frac{R}{S}\)

or \(\frac{2}{4} = \frac{3}{x}\)

or X = 6 Ω

In the circuit ABDC, the resistances P and Q are in series and R and X are in series and both are in parallel.

So equivalent resistance,

∴ Current drawn by the circuit,

I = \(\frac{E}{3.6+2.4}= \frac{6}{6}\) 1A